Man, this debate takes me back to those late-night comic book discussions with my friends! Supergirl's power levels have fluctuated so much across different continuities that it's hard to give a definitive answer. In many modern interpretations like the 'Supergirl' TV series and recent DC comics, she's portrayed as nearly equal to Superman in raw strength, sometimes even surpassing him when her emotions run high.
What fascinates me is how their powers manifest differently - Superman has decades of experience controlling his abilities, while Supergirl often fights with this wild, untapped potential that makes her unpredictable. Remember that 'Red Daughter' arc where she went toe-to-toe with Clark? Pure cosmic fireworks! At the end of the day, I think it depends which writer you ask - but emotionally, I'll always root for Kara when she cuts loose.